This invention relates to a testing device and more particularly to an improved testing device for testing hydraulic circuits such as the brake system of a motor vehicle.
The need for testing of hydraulic circuits is well known. This necessity is particularly true in connection with the braking system for motor vehicles to insure that a vehicle embodying a defective braking system will not be delivered to the ultimate consumer. Devices have been proposed for testing such circuits by applying a pressure to the actuator of the circuit, either the brake pedal or the piston of the master cylinder, and sensing for leaks through either loss of pressure, excessive travel during a given time period or a combination of these factors. Prior art devices have all required separate components for sensing travel and pressure or have not directly measured either travel and/or pressure applied to the actuating element of the brake system. Where separate components are used, the setting up of the testing device is particularly cumbersome, particularly when used in an assembly line environment. In addition, the necessity of setting up separate elements introduces the possibility of error into the testing system.
Where the device does not directly sense pressure applied to the actuating element of the brake system, but rather interpolates it from the fluid pressure in the actuator of the testing device, such devices also introduce the possibility of inaccuracies, particularly where the hydraulic system of the actuating device may introduce errors which cancel out the effect of defects in the actual brake system.
It, therefore, a principal object of this invention to provide an improved simplified and yet accurate device for testing hydraulic systems.
It is a further object of this invention to provide an improved brake testing device, particularly adaped for directly actuating the master cylinder unit of an automotive braking system.